SERPENT和SAFER密码算法的能量攻击

摘要

SERPENT and SAFER are AES candidates, which are analyzed by power attack in this paper. It is shown that power attack needs 2159、2119 and 279 trials for 256、192 and 128 bits key- SERPENT respectively. Although the number of trials is too big to realize, it reduces greatly the size of key. SERPENT have many weak keys for power attack. By analyzing and computing, it is received that SAFER is broken to power attack. Finally, some suggestions and two improving key scheduling of SERPENT are given.%SERPENT和SAFER是AES的两个候选算法，本文使用能量攻击方法对它们进行了深入分析，结果表明：对于256、192和128比特密钥的SERPENT算法，能量攻击平均需分别进行2159、2229和279次试验。虽然所需的试验次数实际没法达到，但是此攻击方法大大地降低了SERPENT的密钥规模，并且发现对于能量攻击，SERPENT有许多弱密钥。经过深入分析和穷尽搜索可知：能量攻击可以获取SAFER的种子密钥。文中还给出了两种抵抗能量攻击的SERPENT的改进密钥方案以及设计密钥方案时需注意的问题。